1. Field of the Invention
The present invention relates to a color test strip carrying a pad for correction. More particularly, the present invention relates to an improvement of a color test strip for analyzing components contained in a liquid sample such as urine.
2. Description of the Related Art
Japanese Patent Kokai Publication No. 101491/1978 and corresponding U.S. Pat. No. 4,160,646 disclose a composite color test strip carrying a pad for correcting reflectance and various coloring pads and a method for analyzing various unusual materials contained in a sample by measuring the developed colors with various lights having different wavelengths to avoid influence of a colored sample. In the invention of this Japanese Patent Kokai Publication, the pad for correcting reflectance is made of a plain filter paper which is also used as a base material of the coloring pads and is not specially treated.
In general, when a material contained in a colored sample is measured with the coloring pad, different coloring substances have influences on tested items at different degrees, and a correction effect of the pad may be influenced by such coloring substances.
For example, when a concentration of nitrate in urine containing blood at a high concentration is measured, an untreated filter paper as a correction pad-can avoid a false positive result, but sometimes a false negative result may be obtained.